Play fast and loose

To play fast and loose is to be unreliable, inconstant and deceitful. The idiom dates from the 1500s and derives from a cheating game called fast and loose that was played in The Middle Ages whereby gullible spectators would be invited to make a stick fast or bound with a belt or rope, only for the trickster to extract the stick easily and quickly. By the 16th century, it had acquired its current figurative meaning. Shakespeare refers to the original cheating game in Antony and Cleopatra Act IV, Scene XII, “Like a right gypsy, hath, at fast and loose, beguiled me” and also to the figurative meaning in King John Act III, Scene I, “Play fast and loose with faith? So jest in heaven.”